Biopsychology Quiz 3: Neuron Communication

Which of the following best describes what happens once an action potential is created and starts down an axon? a) It travels all the way down the axon at the same speed. b) It travels all the way down the axon but loses speed slightly as it travels. c) It can travel all the way down the axon but also can stop and reverse the direction due to a repolarization pulse happening at a node of Ranvier. d) It travels all the way down the axon but picks up speed slightly as it travels. e) The speed of the action potential is in direct proportion the intensity of the signal at the axon hillock. The greater the intensity, the faster the speed.

a) It travels all the way down the axon at the same speed.

In an action potential, there is a time when the neuron cannot send another signal. This is during the depolarization and repolarization process. This is called the a) absolute refractory period. b) relative refractory period. c) constant refractory period. d) complete refractory period. e) contingent refractory period.

a) absolute refractory period.

Connexons make up ______________ in an electrical synapse. a) gap junctions b) Ca++ ion channels c) sodium-potassium pumps d) post-synaptic receptors e) synaptic plates

a) gap junctions

Which type of neurotransmitter receptor affects ion channels through a second messenger system? That is, this type of receptor does not bind to ion channels directly. a) metabotropic b) anabotropic c) ionotropic d) chemotropic e) introtropic

a) metabotropic

Where does an axon potential begin on an axon? a) the axon initial segment (AIS) b) the first node of Ranvier c) the action-potential initiating hillock (APIH) d) the first axon-collateral segment (ACS) e) the bouton segmentalis

a) the axon initial segment (AIS)

____________is the most common inhibitory neurotransmitter in the brain. a) Serotonin b) GABA c) Glutamate d) Acetylcholine e) Glycine

b) GABA

Which is the most common excitatory neurotransmitter? a) GABA b) dopamine c) glutamate d) substance P e) serotonin

c) glutamate

What causes depolarization of a neuron membrane potential? a) the sodium-potassium pump using ATP to move ions against their gradient b) potassium (K+) channels opening, allowing K+ ions to enter the neuron c) potassium (K+) channels opening, allowing K+ ions to exit the neuron d) chloride (Cl-) channels opening, allowing Cl- ions to enter the neuron e) both K+ and Cl- channels opening and both exiting the neuron

c) potassium (K+) channels opening, allowing K+ ions to exit the neuron

When do voltage-gated ion channels open along the axon? a) when the membrane around them is repolarized to any degree b) when the membrane around them is depolarized to any degree c) when the membrane around them is depolarized to their threshold potential d) when the membrane around them is repolarized to their threshold potential e) when they are activated by a neurotransmitter or hormone

c) when the membrane around them is depolarized to their threshold potential

The amino acid phenylalanine is the precursor for which of the following neurotransmitters? a) dopamine b) norepinephrine c) epinephrine d) All of the above are correct. e) None of the above are correct.

d) All of the above are correct.